P0606critical severityPowertrain
PCM Processor Fault
on 2021 Subaru Legacy 2.5L H4 · AWD
What this code means
The PCM has detected an internal processor error.
Symptoms
- Check Engine Light
- Erratic operation
- Possible no-start
- Multiple fault codes
Common causes
- PCM internal failure
- Power supply issue to PCM
- Severe voltage spike
- PCM overheating
Diagnostic steps
- Check PCM power and ground circuits
- Look for water or heat damage
- Check for voltage spikes
- Try PCM reprogramming
Repair notes
Usually requires PCM replacement. Check power and grounds first.
Other Powertrain codes on this vehicle
P0001
Fuel Volume Regulator Control Circuit/Open
P0002
Fuel Volume Regulator Control Circuit Range/Performance
P0003
Fuel Volume Regulator Control Circuit Low
P0004
Fuel Volume Regulator Control Circuit High
P0010
Intake Camshaft Position Actuator Circuit/Open Bank 1
P0011
Intake Camshaft Position Timing Over-Advanced Bank 1
P0012
Intake Camshaft Position Timing Over-Retarded Bank 1
P0013
Exhaust Camshaft Position Actuator Circuit/Open Bank 1
P0014
Exhaust Camshaft Position Timing Over-Advanced Bank 1
P0015
Exhaust Camshaft Position Timing Over-Retarded Bank 1